【正文】 s obvious. Ichthyosaurs were reptilian contemporaries of the dinosaurs, with fins and streamlined bodies. The fossils look like dolphins and they surely lived like dolphins, in the water. With turtles it is a little less obvious. One way to tell is by measuring the bones of their forelimbs.Walter Joyce and Jacques Gauthier, at Yale University, took three measurements in these particular bones of 71 species of living turtles and tortoises. They used a kind of triangular graph paper to plot the three measurements against one another. All the land tortoise species formed a tight cluster of points in the upper part of the triangle。s theory of evolution.If you go back far enough everything lived in the sea: watery alma mater of all life. At various points in evolutionary history, enterprising individuals within many different animal groups moved out onto the land, sometimes even to the most parched deserts, taking their own private sea water with them in blood and cellular fluids. In addition to the reptiles, birds, mammals and insects which we see all around us, other groups that have succeeded out of water include scorpions, snails, crustaceans such as woodlice and land crabs, millipedes and centipedes, spiders and their kin and various worms. And we mustn39。t yet discovered.BIn discussing whether we are alone, most SETI scientists adopt two ground rules. First, UFOs (Unidentified Flying Objects) are generally ignored since most scientists don’t consider the evidence for them to be strong enough to bear serious consideration (although it is also important to keep an open mind in case any really convincing evidence emerges in the future). Second, we make a very conservative assumption that we are looking for a life form that is pretty well like us, since if it differs radically from us we may well not recognize it as a life form, quite apart from whether we are able to municate with it. In other words, the life form we are looking for may well have two green heads and seven fingers, but it will nevertheless resemble us in that it should municate with its fellows, be interested in the Universe, live on a planet orbiting a star like our Sun, and perhaps most restrictively, have a chemistry, like us, based on carbon and water.CEver when we make these assumptions, our understanding of other life forms is still severely limited. We do not even know, for example, how many stars have planets, and we certainly do not know how likely it is that life will arise naturally, given the right conditions. However, when we look at the 100 billion stars in our galaxy (the Milky Way), and 100 billion galaxies in the observable Universe, it seems inconceivable that at least one of these planets does not have a life form on it。 stomach contents reveal that most had not been feeding as they stranded. There were also some new theories, which link strandings to hunmans. A growing concern is that loud noises in the ocean cause stranings. Noises such as these caused by military exercises are of particular concern and have been pinpointed as the cause of some strandings of late.One of these, a mass stranding of whales in 2000 in the Bahamas conincided closely with experiments using a new submarine detection system. There are several factors that made this stranding stand out as different from previous strandings. This led researchers to look for a new cause. For one, all the stranded animals were healthy. In addition, the animals were spread out along 38 kilometers of coast, whereas it39。ll be travelling to, where sometimes the tide goes out suddenly, confusing the animals. However, there are many other theories about the causes of mass strandings.The first is that the behavior is linked to parasites. It39。s move on to writing now...聽力Section4Good afternoon everyone. Well, with some of you will go out on fieldwork it39。t like that but now I realise that reading those long articles was good preparation for the things I need to read now. Also, in class we regularly had speedreading tasks to do, and we kept a record of our reading speed, so the teachers were encouraging us to work on that.H: That39。s any time left over for anything extra. My reading speed is still quite slow, though I39。ll have to work hard to find some interesting points. What help you to find these ideas?H: I think that one thing that helped me with this was the reading. I39。ve been trying to speak up more and I just jump in. And I39。s habits, they can let each other into the discussion.H: You39。ve not said anything in our tutorial discussions. Not a word.H: Really, Spiros, why is that? Do the other students talk too much? S: It39。t fell any real sense of satisfaction. I didn39。s free membership of the Bradcaster Gym. All entrance will receive a special Sports calendar with details of all Bradcaster fixtures in the ing year.One of the special opening offers is a fitness test a plete review of your cardiac fitness and muscle tone, actually done in the shop by qualified staff. This would normally cost 30 pounds but is available at half price for this month only. There are only a limited number of places available for this, so to make a booking phone 560341. In addition, if you open an account you get lots more special offers including the chance to try out the equipment at the special opening evenings...聽力 Section3Pro: Before we start, Spiros and Hiroko, thanks for ing in today to talk about your recent study experiences and congratulations to you both in doing so well in the first semester exams. I39。s ing along to open the shop, and he will be stay around until about the midday to chat to any fans who want to meet him and sign autographs.Then there will be a whole range of special attractions all weekend. There will be free tickets for local sporting events for the first 50 customers, and also a special petition open to all, just answer 15 out of 20 sports questions correctly to win a signed copy of Paul King39。t got ex